Drafting- device



March 20, w28. 1662882 F. A. CLARK DRAFTING i'DEVICE Filed June4 20, 1922 wnniiimmmmg IM C nnnmnngmmmgngngnummmuu www@ Patented Mar. 20, 1928.

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IFR/EDFRIICKA A. CLARK, OF DAYTON, OHIO.

DRAFTING DEVICE.

Applicationled .Tune 20, 1922. Serial No. 569,672.

portion vof the mask forming the subjectV matter hereof. Fig. 3 is a detail perspective View. Fig. 4c is a similar view of a modification. Fig. 5 shows a mask adapted for drawing dotted curved lines. Fig. 6 is a group of broken lines of different characteristicsr produced by the device forming the subject matter hereof.

Like parts are indicated by similar characters of reference throughout the several views. .v

The present invention is ofv extremely simple character, comprising a piece of sheet material 1, having-therein a plurality of perforations 2 arranged in rows and uniformly spaced one from the other. The sheet 1 may have therein'one or more rows of perforations, which perforations may befof different sizes, or may begrouped in various combinations. For convenience and to afford a range or latitude whereby the device need not be so accurately positioned, the perforations 2 are preferably a succession of slots. The width of the slots is approximately equivalent to the length of the dash or mark to be produced, while the intervening bridging portions 3 are substantially equal in width to the. intervening spaces between the succession of dots and dashes comprising the broken line. In practice, the slots 2 are made slightly wider than the length of the desired dash, while the intervening protective vor bridging portion 3 are slightly less in width than the desired spaces, to allow for the Vrise and drop of the pen or pencil when passing into and out of the slots or perforations 2. In the plan view Fig. 2, the perforations have been shown arranged in four series or rows. The row A comprises a succession of slots of equal width, spaced equal distances apart, and serve to produce a vdotted line of the character illustrated at A, in Fig. 6. The second row of perforations are slots of greater width than those of the initial series, and are for the purpose of producing a dash line, such as shown at B in Fig. 6. In the drawing, the perforations of the second series B, have been shown equivalent to two of the initial slots A, with the.

intervening protective portions or bridging strips 3 removed. The third series or row of perforations shown in Fig. 2 and indicated at C, comprises a combination of the holes or perforations of the rows A and B, arranged alternately. This combination produces an alternating dot and dash line, shown in Fig. 6 at C. The final row or series of perforations D in Fig. 2 comprises one large perforation, alternating with two of the narrow slots or perforations, and enables the production of a dash and double dot line shown at D in Fig. 6. It will be understood that the extent of the slot or perforation and also the width of the intervening protective or bridging portion may be varied according to the whim of the draftsman or the condition of use.

In using this drafting mask, the perforated sheet is superposed upon the drawing surface 4, as shown in Fig. 1 and a straight edge, T-square, triangle or other template is laid upon the mask 1, with its edge alined with or intersecting the selected series or row of perforations. A marking instrument such as a pencil or pen is drawn along the edge of the Tesquare or template in the usual manner, just as a draftsman would proceed in making a continuous or solid line. This line intersecting the succession of perforations or holes, the drawing instrument will intermittently engage the drawing surface through such holes 2 of the sheet 1 thereby marking the drawing surface at spaced intervals, the intermediate portions of the line being received upon the protective or bridging portion 3 of the mask. While an ordinary flat sheet of material perforated as described may be successfully employed, not only with pencil, but also with a ruling pen for drawing ink lines by exercising a reasonable amount of care, there has been shown in Figs. 3 and 4, means by which the protective portion or bridging strips 3 of the mask are elevated slightly above the drafting surface 4. This may be effected by forming in the mask or sheet 1, crimps or beads 5, parallel with the rows of perforations. These crimps or beads 5, resting upon the drafting surface ric Acatedfat .itsjpoint or center. .able the mask to be shifted to and fro within 4 will support the bridging portions or protective portions 3 slightly above the surface Ll. The material of the strip being flexible or elastic will readily yield as the pen or `pencil passes thereover, and will immediately spring up to avoid blotting the line when ink is being employed. In Fig. 4L there are shown l'auxiliary strips 6, in the form of elongated cleats cemented to the underside Vofthe mask form- .ing spaced supports in lieu of the crimps or beads 5. These strips or cleats G perform .a like function -of elevating the protective portions of the mask. However, as before mentioned, .byexercise of reasonable care in drawing ink lines, such elevating supports ,may be entirely dispensed with. For the purpose oflproducing curved lines of 'broken character, a sheet may be provided as shown inlilig. 5,having therein rows of Aperforations concentrically arranged. This sheet maybe `either .circular or sector shape in form, land @either provided with a central enlarged openingy for the center leg of the compass, Vor if -a vsector `shape sheet, it may be trun- This `will en- V.limited range in relation -with the center .multiplied and grouped with endless variety.

From the above ydescription -it will heap- Vgparent that there-is thus A,provided a device `of the Lcharacter'described possessing thepar- `ticular features of advantage before -enumerated as desirable, but which obviously fis Asusceptible l,of modification in its form, fproportions,.deta1l .construction and arrangement of parts without departing from the `principle involved or "sacrificing `any of its advantages Y While in order to comply with the statute `the invention'hasbeen described in language more or less specific as to structural features,

it 'is to be understood that the invention isnot limited to the specific details shown, but

*thatthe `means "and construction herein disnormally iiat strip-of thin flexibletranspar-V ent material having therein a series of spaced perforationsarranged in rows and longitudinally disposed crimpsfforme'd intermediate the rows of perforations ,and -extending substantially parallel therewith 4and formingintegral ribs normally supporting lthe perforated portionslof the Astrips in slightly elevated position, the strip "being adapted 'tobe slidingly `inserted edgewise 'intermediate a straight'ed'ge and 'a drafting surface'to vsuch extent that the directing margin of the straight edge will intersect said perforations,

the perforated r,portions of the strip intermediatethe/longitudinal crimps being depressible vinto'fcontact Awith the `drafting 'surface, -wherebyfa Iline drawn "along the .straight edge will be produced :intermittently VVupnn the drafting surface. w u

In testimony whereof ,-I have hereunto'set myhand this thrda vofJune, A. D. 1922.

SFREDE 'IGK A. CLARK.

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